Summary The pilot of the Robinson R22Beta helicopter (serial number1398, registration C-FQDQ) was operating in an area about 10nautical miles north of Courtenay, British Columbia, giving rides to volunteer interns at a local avian rescue society. He had completed four trips, then shut down and readied the helicopter for a flight to Courtenay Airpark, where he would refuel before returning to his home base at Boundary Bay Airport. On start-up, he ran the helicopter on the ground for about two minutes after re-engaging the clutch. At approximately 1630 Pacific daylight time, the pilot lifted off, turned the helicopter 180degrees to point toward his departure path, and raised collective to perform a confined-space take-off. The helicopter climbed to a height of about 60feet above ground level when there were abnormal engine sounds and an apparent detonation. The engine became quiet, and the main rotor blades were almost stopped. The helicopter rotated about 270degrees to the left in a rapid descent and struck the ground heavily with little or no forward speed. The pilot was severely injured. The helicopter was substantially damaged, but there was no post-crash fire. Ce rapport est galement disponible en franais. Other Factual Information The pilot held a current commercial pilot licence with fixed-wing aircraft and helicopter type endorsements, the latter obtained in January1987. He had owned the helicopter since1993, and had flown all of its accumulated 1660.6hours, except for 245.9hours that were accumulated in the United States before the helicopter was imported and rebuilt subsequent to a roll-over accident. The pilot had 32years of experience flying with commercial airlines. At the time of the accident, the weather conditions were suitable for flight in accordance with visual flight rules. The 1600 Pacific daylight time1 weather for Comox (10miles southeast) was reported as wind 020True at 4knots, visibility 20statute miles, ceiling 7000feet, temperature 19C, and dew point 12C. Rain showers occurred at the site soon after the accident. The site elevation was about 300feet above sea level. The helicopter was powered by an Avco LycomingO-320 B2C160-horsepower (hp) engine, de-rated to 124hp maximum continuous power. The helicopter was being operated with 100LLAVGAS. It is a governed engine, meaning that a constant rpm is maintained during power transients as commanded through collective lever positioning. The pilot monitors the engine manifold pressure gauge to ascertain the power being produced. The pilot had checked available power prior to and during the rides given and found it normal. He used about 24inches of manifold pressure for his confined-space take-off. The pilot did not recall applying carburetor heat prior to departure or during take-off. The helicopter was equipped with a carburetor heat gauge that indicates temperature at the carburetor. The gauge has a yellow warning band between -15C and 5C. The gauge is placarded to advise the pilot to apply full carburetor heat and ignore the gauge below 18inches of manifold pressure. The Robinson Helicopter Company Pilot's Operating Handbook states that operation within this carburetor temperature range (yellow) without carburetor heat must be avoided at any power setting. According to the carburetor icing chart in Aeronautical Information Publication (A.I.P.Canada), Section AIR2.3, an air temperature of 19C and a dew point of 12Cfall in the moderate icing at cruise power or serious icing at descent power sector (seeAppendixA). Indicators of carburetor ice would normally be a drop in manifold pressure and engine rpm. Severe icing will result in engine stoppage. The Robinson Helicopter Company Pilot's Operating Handbook states, The pilot may be unaware of carburetor ice formation as the governor will automatically increase throttle and maintain constant manifold pressure and rpm. The helicopter is equipped with a low-inertia rotor, susceptible to rapid loss of rotor rpm if mishandled. If rotor rpm significantly decreases at a slow airspeed, rotor stall may be inevitable. The Robinson Helicopter Company Pilot's Operating Handbook provides Safety Notices regarding low-rotor stall and carburetor ice.2 The accident helicopter was examined at the TSB regional facility. This examination revealed the following: The engine and related systems were deemed to be in an acceptable condition to allow the engine to be run. The engine was tested at a manufacturer-approved engine overhaul and repair facility and found capable of producing full power. A 5-amp fuse was found installed where a 1.5-amp, in-line fuse prevents the belt-tension actuator from overloading the drive belts. The carburetor heat control was found in the COLD/Unheated air position. Impact marks indicated that the carburetor heat guillotine slider valve was opened to allow the intake of filtered but unheated outside air. The fuel system was intact and serviceable, there were no fuel leaks, and the main tank contained 22litres of fuel. The pilot had installed a portable global positioning system (GPS) unit and temporarily secured it with clecos3 onto the side of the instrument console. It was powered continuously from a terminal at the clutch tensioner switch and protected with a 2-ampfuse. During the 12-year inspection, which was started on 25April2005 and completed on 16May2005, about 32.5flight hours before the accident, it was found that the left-side collective push-pull (P/P) tube glued-on protection sleeve (P/N A143-1) and the guide bushing (P/N C439-9) were worn. The tube and the guide support bracket (P/N A432-1) had worn excessively when the guide bushing (P/N C439-9) had been extruded from the bracket during operation. In this original installation, the guide support bracket had a guide bushing (P/N C439-9) inserted and trapped between two metal layers of the guide bracket. A guide bushing was substituted during the 12-year inspection and a substitute airworthy P/P tube was re-installed. On the day of the occurrence, at 1659.9airframe hours, a collective P/P tube guide upgrade kit (P/N KI-130) was installed. A new fuel sender unit (P/N A550-1) was installed due to faulty fuel quantity measurement. The fuel gauge was calibrated before the pilot refuelled for his trip to the aviary.